Computer graphics processing and selective visual display system – Animation processing method – Iterative display of preconfigured images
Reexamination Certificate
2001-05-30
2004-07-20
Shalwala, Bipin (Department: 2673)
Computer graphics processing and selective visual display system
Animation processing method
Iterative display of preconfigured images
C345S520000, C348S014160, C348S014160, C348S014160, C348S211130, C348S409100, C348S441000
Reexamination Certificate
active
06765599
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an image signal transmission apparatus for transmitting image signals produced in a personal computer to a display device, such as a liquid crystal projector, plasma display panel (PDP) or the like, which is relatively remote from the personal computer.
2. Description of the Prior Art
[1] In a case of transmitting image signals produced in a personal computer to a display device via an analog transmission cable, if the analog transmission cable is long, it is apt to cause image deterioration. Such image deterioration will be noticeable especially on the display device having a high resolution of 1024.times.768 pixels (XGA), 1280.times.1024 pixels (SXGA) or the like.
Some image signal transmission apparatus have already been developed that cause no image deterioration even when the transmission cables are long. An example of those apparatus is “PanelLink” by Silicon Image, Inc. in the United States, which has been developed based on a signal transmission technology called TMDS (Transition Minimized Differential Signaling).
According to this signal transmission technology of TMDS, red, blue and green signals (RGB) and a clock signal are serially transmitted in a differential method. This differential method, which is a method for transmitting a single signal by use of two transmission lines, realizes noise immunity and a stable signal transmission and further achieves a high transmission speed and a long-distance cable transmission. It becomes, however, difficult for this method to provide such transmissions if the resolution of image data is further raised up to an ultrahigh resolution of 1600.times.1200 pixels (UXGA), 2048.times.1536 pixels (QXGA) or the like which causes the transmission cable to reach its own physical limit. As a solution to this problem, there has been proposed “Dual Link Method” by the DDWG (Digital Display Working Group) in its DVI (Digital Visual Interface) specification. Unlike the conventional “PanelLink” (which will be referred to as “Single Link” method in contrast to the “Dual Link” method hereinafter), the “Dual Link” method transmits the R, G, and B signals, by use of not a respective single channel for each signal, that is, three channels but two channels for each signal, that is, six channels, after performing a one-phase to two-phase conversion of each signal. In this way, the “Dual Link” method can ensure a bandwidth that is twice as wide as that of the “Single Link” method, allowing the image transmission of an ultrahigh resolution, such as UXGA, QXGA or the like. Additionally, the one-phase to two-phase conversion of each signal can reduce the required transmission rate and hence realizes the signal transmission through a longer cable.
FIGS. 1 and 2
show the structures of signal transmission apparatus employing the “Single Link” and “Dual Link” methods, respectively.
In the signal transmission apparatus employing the “Single Link” method, a PanelLink transmitter
301
receives image data represented by parallel signals and performs a parallel-serial conversion of the image data from the parallel signals to serial signals. The image data of serial-converted signals are transmitted through a cable
302
to a PanelLink receiver
303
. The cable
302
comprises three pairs of signal lines for transmitting the image data and one pair of signal lines for transmitting a clock signal. The PanelLink receiver
303
performs a serial-parallel conversion of the received serial signals to the parallel signals.
In the signal transmission apparatus employing the “Dual Link” method, the even data of image data represented by parallel signals are applied to a PanelLink transmitter
401
, while the odd data of the image data are applied to a PanelLink transmitter
402
. The PanelLink transmitters
401
and
402
each perform a parallel-serial conversion of the received image data from the parallel signals to serial signals.
The even data of the image data that have been converted into the serial signals by the PanelLink transmitter
401
are transmitted through a cable
403
to a PanelLink receiver
404
. The odd data of the image data that have been converted into the serial signals by the PanelLink transmitter
402
are transmitted through the cable
403
to a PanelLink receiver
405
. The cable
403
comprises six pairs of signal lines for transmitting the image data and one pair of signal lines for transmitting a clock signal. The PanelLink receivers
404
and
405
each perform a serial-parallel conversion of the received serial signals to the parallel signals.
The object of the present invention is to provide an image signal transmission apparatus that allows the transmission of image signals to be done by use of a transmission method suitable for the resolution of the image signals.
[2] If, in the “Dual Link” method of
FIG. 2
, the RGB image data represented by the parallel signals are not separated into even and odd data but are applied to the PanelLink transmitter
401
as they are, and if the PanelLink receiver
404
only is activated, while the PanelLink transmitter
402
and PanelLink receiver
405
not being activated, then it would correspond to the “Single Link” method of FIG.
1
.
It is difficult for the “PanelLink” method to effect the transmission of an ultrahigh resolution, such as UXGA, QXGA or the like, and/or effect a long-distance transmission. Thus, in the case of effecting such an ultrahigh resolution transmission and/or a long-distance transmission, the “Dual Link” method is effective.
On the other hand, in the case of transmitting the signal of a low-resolution, such as VGA or the like, the “Single Link” method works to a sufficient degree. In addition, because of an increasing demand for portability of the apparatus on the image transmitting side, such as a personal computer or the like, and that on the image receiving side, such as a liquid crystal projector or the like, the need to reduce the power consumption has become important. Thus, when a low-resolution signal is transmitted or when no long-distance transmission is required, it is more desirable to effect the signal transmission by use of the “Single Link” method.
The object of the present invention is to provide an image signal transmission apparatus that allows the transmission of image signals to be done by use of a transmission method suitable for the resolution of the image signals and for the cable length. [3] In a case of transmitting image signals produced in a personal computer to a liquid crystal projector via an analog transmission cable, if the analog transmission cable is long, it is apt to cause image deterioration. Such image deterioration will be noticeable especially on the liquid crystal projector having a high resolution of 1024.times.768 pixels (XGA), 1280.times.1024 pixels (SXGA) or the like.
There have already been developed some image signal transmission apparatus that can avoid image deterioration even when the transmission cable is long. An example thereof is “FPDLink” developed by National Semiconductor Corp. in the United States. This image signal transmission apparatus is also called “LVDS.”
Another example is “PanelLink” by Silicon Image, Inc. in the United States.
FIG. 3
shows the structure of “PanelLink,” which comprises a graphics controller (graphics board)
151
built in a personal computer, a transmitting-side unit
152
, a receiving-side unit
153
, and a cable
154
for connecting the transmitting-side unit
152
and the receiving-side unit
153
.
The transmitting-side unit
152
includes an encoding/parallel-serial converting circuit
161
, a PLL circuit
162
, and an amplitude control circuit
163
. The encoding/parallel-serial converting circuit
161
receives image data, DE (i.e., a display enable signal for discriminating between a display mode and a standby mode), and a control signal from the graphics controller
151
.
In the encoding/parallel-serial converting circuit
161
, a parallel-serial conversion of the 24-bit
Kasamatsu Hideki
Nagai Takaaki
Arent Fox PLLC.
Kovalick Vincent E.
Sanyo Electric Co,. Ltd.
Shalwala Bipin
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